Shaping the Rings of Molecules 21 February 2020

Shaping the rings of molecules 21 February 2020

And that could be a boon for the making of pharmaceuticals and electronics, they say.

"The shapes of the macrocycles we have made is what makes them special—they are what we call planar chiral," said Collins. "And the planar chiral topology controls how the molecules interact with nature. In general, macrocycles with planar chirality are underexplored, because chemists usually have a lot of trouble making them."

Until now, they had two choices: perform multi-step

syntheses that are tedious and wasteful, or they could exploit methods that employ catalysts based Model chiral macrocycle (shown in blue) in the catalytic pocket of the enzyme CALB (shown in grey, catalytic on elements that are toxic, expensive and non- serine 105 colored in green [PDB ID 5GV5]). The figure abundant in the Earth's crust, such as ruthenium was generated using The PyMOL Molecular Graphics and rhodium. System, Version 1.2r3pre, Schrödinger, LLC. The docking of the macrocycles was carried out with the Both approaches have long frustrated chemists, Fitted program from the Forecaster computational and Collins' team looked for an alternative. They platform. Credit: Université de Montréal found it in biocatalysis, a process that uses enzymes, biological and typically non-toxic catalysts, as a solution to preparing planar chiral macrocycles. Macrocycles are molecules made of large rings of atoms. Despite being relatively big and flexible, the Remarkably, even though chemists had never molecules don't always stay "floppy"—they can before explored biocatalysis for the synthesis of actually lock themselves into specific shapes and planar chiral macrocycles, it turned out there was a geometries. commercially available product that could prepare the macrocycle: a lipase enzyme called CALB. In manufacturing, controlling the three-dimensional shapes of macrocycles is critical. It helps decide, Using it, the biocatalysts were able to shape the for example, whether the aroma in a perfume is macrocycles in often near-perfect selectivity, even unique or whether a prescription drug will work on though the enzyme had not evolved for that a particular disease. purpose.

But for synthetic chemists, those who study the Importantly, Collins and his team came up with a construction of molecules, controlling the topology synthetic plan that involved using simple molecular of the large rings has not been a straightforward building blocks to "decorate" macrocycles with process—until now, that is, thanks to research done functionality. "Functionality are handles, or simple at Université de Montréal. groups of atoms that be easily transformed into arrangements that are more complex," Collins In a study published today in Science, a team led explained. by chemistry professor Shawn Collins reports they have succeeded in using a natural process called "Our hope is that the macrocycles can now be biocatalysis to control the shapes of macrocycles. tailored to impact industry. Planar chiral

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macrocycles have already been known to act as antibiotics and anticancer agents. Applications in electronic materials—in lasers and display devices, for example—could be possible using the approach."

More information: Christina Gagnon et al, Biocatalytic synthesis of planar chiral macrocycles, Science (2020). DOI: 10.1126/science.aaz7381

Provided by University of Montreal APA citation: Shaping the rings of molecules (2020, February 21) retrieved 1 October 2021 from https://phys.org/news/2020-02-molecules.html

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